OK, the clunking noise will probably be one of two things. Either you've damaged your driveshaft CV joint through excessive lowering or the spring isn't seated correctly and is skipping on the seat. The first will sound like a 'clunk - clunk - clunk' whilst you're driving on full lock. The latter will make a single clunk or bang when you first reach full lock.
As to the whole idea of running out of adjustment on a coilover kit, i'm rather concerned for your safety since this indicates the spring will not be suitable for the area of adjustment you're looking for. I assume you're after a cosmetic for shows / cruising? If not you should be aware that you're probably making the handling and roadholding of your car dangerous if driven at pace. For example, the fact the springs are not pre-compressed indicates they will not correctly support the weight of the car throughout the handling envelope. You may find that under hard cornering the bump stops will bind and cause very rapid switch to oversteer / understeer. You'll probably bind the bump stops under braking too, which will cause you to loose grip on uneven sufaces.
I knew a guy with a Focus ST who hit a tree because his rear bump stops binded up when cornering hard and going over a slight dip. He survived but the car didn't.
As you reduce the ride height you need to fit shorter and stiffer springs. Because a stiff spring will require less travel to generate the same load supporting force, you don't need to wind down the spring pan adjuster so much, also because the spring is shorter, it's automatically reducing the set height. Ultimately though, on a coilover you should never have slack unless you're doing competition track / rally work where you may use a tender spring. Not appliccable here though.
Do you have the spring rates and free (uncompressed) spring lengths? Along with the damping rates this info should have come with the kit. If so i could advise what you'd need.
